JOHNSTON, Iowa – Gov. Tom Vilsack said he's received a letter with details of his birth that could help him track down his birth mother.

Vilsack, who has been open about his adoption in Pittsburgh, said he hasn't decided what to do with the information and will ponder the matter over the holidays.

"You have to have time to think about things like this," said Vilsack, speaking Friday after the taping of a public affairs show on Iowa Public Television. "This is a decision nobody else can make."

The matter could focus greater attention on Vilsack's personal history as he prepares to leave the governor's office and pursue the Democratic presidential nomination.

Vilsack, 56, was adopted shortly after birth and has spoken of growing up in a family where his adoptive mother struggled with alcoholism and his adoptive father had financial setbacks. He has used his past as an example of rising above adversity, but the latest development could add detail to the story.

Vilsack said the letter arrived at his presidential campaign offices in Des Moines and he almost discarded it, thinking it was yet another holiday solicitation.

"You get a lot of solicitations this time of year," said Vilsack.

Instead, he opened it and read a letter from a nun who had served at a home for unwed mothers.

"It was a place for young women to go to have their babies and then decide whether to leave them there," Vilsack said.

Vilsack's mother decided to leave her son at the home.

In the letter, the nun told Vilsack that the records of his birth were still available, should he choose to find out details.

Vilsack said his adoptive mother had told him the records had been destroyed by fire, probably as a way of protecting him from the past. Despite knowing nothing about his parents, Vilsack said he's never been haunted by questions about his past.

"I've never actually had that feeling," said Vilsack.

But he acknowledged that learning about his family history could be useful for medical reasons.

The choice has left him conflicted.

"You have loyalty to the family who raised you," said Vilsack, whose adoptive parents have died.